The present disclosure relates generally to cloud computing, specifically relative to the ability to dynamically adjust computational and storage capacity on demand. The compute capacity can be increased or decreased by adjusting the number of processing units (cores) allocated to a given instance of a processing module (server or node) or by adjusting the overall quantity of processing modules in a system. Cloud computing systems such as OpenStack abstract the management layer of a cloud and allow clients to implement hypervisor agnostic processing modules.
One core technology underlying cloud computing is virtualization. Virtualization enables a single physical machine to run multiple operating systems or operating environments at once. This allows the consolidation of workloads when there is less load, but also the ability to subdivide physical machines, creating additional virtual resources on demand. These additional virtual resources can be configured to have a high degree of uniformity, making the addition of newly-created virtual resources easier to integrate into an existing system.
Another existing technology is called “Wake on Lan” or “WoL.” WoL allows a networked computer to go into a lower power state when it is not being used, while also allowing external management software to wake up the computer by sending an Ethernet frame with a specific structure, called a “Magic Packet.” The Ethernet controller then alerts the system and the power management circuitry wakes it up.
Virtualization allows the migration of computing resources from one host machine to another host machine. Existing techniques typically require the use of shared storage to be able to transfer a virtual machine from one server to the other while it's still running. Shared storage can be inefficient because it can be challenging and expensive to scale in cloud provider environments and may present a single point of failure. Other techniques require the virtual machine to be shut down during the entire period of transfer from one server to another. If the virtual machine happens to be very large in size, the transfer time could take very long periods of time to transfer it from one server to another.
Similarly, Wake-on-LAN allows virtual machines to be awakened under certain circumstances, but the virtual machines must be pre-defined and the use of certain sleep states is less efficient.
It is accordingly desirable to improve virtual machine management, including the processes for waking, migrating, and configuring virtual machines in a cloud computing system.